The article I saw listed all 6 as part of the Mosaic series: Lord of Emperors, Sailing to Sarantium, The Last Light of the Sun, The Lions of Al-Rassan, A Song for Arbonne, and Tigana. Either way I'm sure I'll enjoy them all.
I really enjoyed Laura Joh Rowland's series, reading 16; but towards the end she got pretty mystical and my interest waned. I'll probably return now and read the last 2 in the series: The Shogun's Daughter, and The Iris Fan.
https://www.goodreads.com/author/show/10987.Laura_Joh_Rowland
The article, I feel obliged to point out, is not accurate (I have read all of these books).
The Sarantine Mosaic comprises two books (Sailing to Sarantium, Lord of Emperors), roughly analogous to Constantinople (later Byzantium) in the time of an alternate Justinian and Theodora (fifth century CE/AD).
The closest direct link to that pair of books is River of Stars, which is set in an alternate world - the exact same alternate world as that of the Sarantine Mosaic, , but a thousand years later, - based on the Adriatic Sea, and also taking in Sarantium (Constantinople) a quarter of a century after its fall (in 1453) to Asharite (Islamic) forces.
Apart from Tigana, which is not really part of that world, the other books are tangentially connected with it, - geographically you know that it is the same world, but (apart from a fleeting grace note in Last Light of the Sun) are separate worlds, distant in time and space.
Thus, Lions of Al-Rassan is set in an alternate Spain at the time (11th century) of an alternate El Cid; A Song for Arbonne is set in an alternate Provence during the 13th century; Last Light of the Sun is set in an alternate Wales, England and Viking lands during the ninth century).
Tigana - which is an excellent book - isn't a part of this world at all, apart from the reference to two moons.
Anyway, it may simply be a publicists desire to find common links between the respective books; I think you'll enjoy them all, and I certainly hope that you do.